Iran authorities Thursday executed 23-year-old Mohsen Shekari for protesting the death of Mahsa Amini, according to state-affiliated source Tasnim News Agency. Shekari is the first protester to be executed since Iranians nationwide began protesting Amini’s death in police custody. Amini was arrested on September 14 for wearing her hijab improperly, taken to the hospital in a coma after two hours and was reported dead by police two days later.

Tasmin News Agency reported that Shekari wielded a machete during a protest in Sattar Khan and injured a member of the Basij, an Iranian paramilitary force. Shekari was arrested on October 3, and the Tehran Islamic Revolution Court subsequently found him guilty of moharebeh, or “waging war against God,” and sentenced him to death.

A group of UN human rights experts condemned the execution in a joint statement and noted, “under international law, the death penalty can only be imposed and enforced for offences that meet the threshold of the most serious crimes… and following a legal process that gives all possible safeguards to ensure a fair trial.”

According to the UN, Iranian authorities have confirmed death sentences against 12 other protesters charged with moharebeh and efsad-e fel-arz, or “corruption on earth.” Experts expressed particular concern for musicians Saman Yasin and Toomaj Salehi. Yasin was sentenced to death by the Revolution Court on October 29, and Salehi was indicted but has not yet been sentenced.

The protests have rocked Iran for nearly three months and garnered sanctions from foreign governments. On November 29, Iranian authorities acknowledged the deaths of 300 people during the protests. However, nonprofit Iran Human Rights reports 448 deaths.